The invention is directed to a method for connection setup before a mobile station of a radio communication system as well as to a mobile station configured in this way and to a base station.
The establishment of digital radio communication systems is disclosed in J. Oudelaar, “Evolution Towards UMITS”, PIMRC 94, 5th IEEE International Symp. on Personal, Indoor and Mobile Radio Communications, the Hague, NL, 18 through 22 Sep. 1994, pages 852 through 856, and M. Lenti, H. Hageman, “Paging in UMTS”, RACE Mobile Telecommunications Workshop, Vol. 1, Amsterdam, NL, 17 through 19 May 1994, pages 405 through 410.
The presently existing mobile radio telephone system GSM (Global System for Mobile Communications) is a radio communication system with a TDMA component for subscriber separation (time-division multiple access). Payload information of the subscriber connections are transmitted in time slots according to a frame structure. The transmission occurs block-by-block. Frequency channels adapted to the time grid of the frame structure (RACH random access channel) are also known from the GSM mobile radio telephone system for arbitrary access for the mobile stations. A mobile station that requests a connection setup can send an access radio block in this frequency channel without a frequency channel having been previously allocated to the mobile station. A transmission power control cannot occur given random access, since the transmission conditions are not yet known at the transmitter side. A mobile station therefore usually sends with maximum transmission power for the radio cell. Maximum transmission power is also selected in order to assure that a mobile station located at the edges of the radio cell that transmits an access radio block generates a signal at the base station that is strong enough for a detection. When a plurality of mobile stations simultaneously actuate the random access in the same time slot and frequency band, radio blocks lower in power would not be capable of being interpreted and would have to be re-transmitted at a later point in time by the affected mobile stations. When two or more signals having nearly the same power intensity arrive, both signals may possibly not be detected and must be re-initiated.